HRO! is a free emergency alert and warning app designed for the Hanseatic and University City of Rostock. The app provides current information, alerts, and emergency instructions directly to your smartphone, with the option of push notifications. The app is based on the free nationwide emergency app BIWAPP, with additional Rostock-specific categories. The app integrates messages generated through the national official modular warning system (MoWaS), weather warnings from the German Weather Service, and a link to the water level portal.

The app allows users to customize the categories for which they receive alerts. The messages are sent by the city administration of the Hanseatic and University City of Rostock and other partners. However, the app's instructions do not replace the instructions of authorities, police, and other emergency services on site.

To use HRO! and receive information, a data connection (mobile or Wi-Fi) is required. This can result in costs from your respective service provider. To use the location feature, location services on your smartphone must be enabled.